Fluid turning blades



Dec. 4, 1956 E. A. STALKER 2,772,855

FLUID TURNING BLADES Filed Aug. 3, 1950 i 9' I 7 mmvrox.

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o 2.7723355. FLUID TURNDNGIBLADES Edward A.. Stalker, Bay City; Mic in, assignor to The StalkcnDevelopment. Company, Bay City, Mich, a corporation of Michigan I This invention relates to-blades for compressors and turbines and other machines in which an" interchange of energy with a fluid occurs; n

An object of the present invention is to providea blade which is economical to produce'. i i

Another object is to provide a means of fabricating blades.

Still another object is to provide a bladefformed from sheet metal which requires a minimum of finishing at its joints.

Other objects will appear from the description, drawings and claims.

I accomplish the aboveobjects by the-meansillustratedf in the accompanying drawings in which-- 1 is a plan view ofablade according to the present invention; v k

Fig. 2 is a section along line 2-2 in Fig. 1;"

Fig. 3 isa viewin sideelevation of." a blade lower part before being given the airfoil contour;

I Fig. 4 is a section of the blade upper part; t

Fig. jshows in plan a gang of blade, lower parts partly pressed to shape; 7 o I 1 Fig. 6- is a side elevation of a. portion; of the" gang; of

Fig. 7 is a side elevation of a portion of the: gang-.of blade upper parts; V

Fig; 8 shows the upper gang superimposed on the lower gang 30 and supported. on a fixture;

Fig.9 is a plan view of an individual blade lower part of a modified form; and

Fig. 10 shows a gang of blade upper parts and individual blade lower parts placed in mating relation thereon.

As shown particularly in Fig. 2 the blade 10 is formed in two parts, the upper part 12 and the lower part 14. The latter has the groove or recess 16 near the trailing edge into which the upper part nests. The groove is just deep enough that the upper surface of the blade is fair across the joint 18.

At the leading edge of lower part 14 there is the groove or recess 22 forming a portion of reduced thickness so that the narrow outer part 24 beyond the groove can be bent about the recess into the position shown with a very small nose radius 26.

The lower part with the grooves is shown in Fig. 3 before the part is bent to the shape shown in Fig. 2.

The grooves 16 and 22 and the tapered parts 24 and 28 are preferably stamped or rolled to shape.

The upper part 12 has the groove 30 forming a contoured edge as shown in Figs. 2 and 4 into which the portion 24 fits.

It will be observed that both parts can be rolled'or pressed or milled and that when the two parts are assembled there are no further operations required to form the leading and trailing edges. This is a very important point since machining operations to produce faired surfaces at the leading and trailing edges are very expensive.

While either part may be regarded as a base part which n Patenteidi'Dec. 1956 carries the other or'mating part, for succinctness inthe ciaims i refer to the part 1 4 as a base part or wall and tothe juxtaposed blade parts 12 as complementary parts. The front portion of either wall especially the portions which are curved are called nose portions.

The; blade parts 14 are preferably stamped in a carrier strip of metal 40 and held integral therewith as shown in Fig; 5 by the smallnecks of metal 42 thus constituting a gang or seti of blade parts. The strip may be of any length; and contain any number of blades.

In the -'next operation as shown in Fig. 6 the leading edge portion 24 is bent to'the position shown in Fig. 2 and the; general curvature. is impressed on the part as shown in the latter figure. The blade part is twisted at the neck 42 to an angle of about 45 relative to the plane of'the strip at its ed'ges 46 and 48. v

f The upper parts 12 are formed in a strip 50in a manner s ir'nilar-to that of the lower parts 14. Suitable lengths of the two strips areimposed one on the other as shown irr Fig. Sand-located by the pins 54 (offixture 51) passi'ngthrough the holes 52 in the strips 40 and 50. The complementary" parts to'form a blade are thus brought intoregistration or mating relation. The juxtaposed strips illand 50 held in place by the pins 54 on the fixtore El are passed through a brazing furnace to braze the joints-at the leading and trailing edges of each blade assembly; The brazing material may be inserted or painted on the parts at the joints just before the blade partsgare brought into mating relation.

After removal from' the furnace the blade necks may be'sawedthro'ugh to free the blades from the strips.

ried in strips, just one strip of blade parts may be used and the mating parts may be individually made and placed-in mating relation on the strip.- Such an individual matingpart is shown in Fig. 9 as 14 Fig. 10 shows such-mating part placed onparts 12.

Prefer" to" the end portions 24 and 28 as being outside oroutwardly of the grooves 22 and 16 respectively.

Although the carriers are shown in the figures as being straight, they may also be arcuate or any other shape.

While I have illustrated a specific form of this inven tion it is to be understood that I do not intend to limit myself to this exact form but intend to claim my invention broadly as indicated by the appended claims.

I claim:

1. A hollow sheet metal fluid turning blade having leading and trailing edges and a predetermined airfoil contour as assembled comprising a base wall-of sheet metal shaped to form the lower face of said blade and having spanwise recesses inwardly of and adjacent both leading and trailing edges thereof forming portions of reduced thickness substantially at the leading and trailing edges less than that of the adjacent portions of said base wall, said reduced thickness portion adjacent the leading edge being folded upon itself, forming a short radius bend the outer surface of Which defines the nose of the blade, and a complementary blade wall of sheet metal supported in mating relation on said base wall, said complementary wall being shaped to form the upper face of said blade and having a contoured edge fitting within and fairing with said tapered marginal edge of said base wall, said walls being bonded together at the contiguous interfitting portions thereof. 7

2. A hollow sheet metal fluid turning blade having leading and trailing edges and a predetermined airfoil contour as assembled comprising a base wall of sheet metal shaped to form the lowerface of said blade and having spanwise recesses inwardly of and adjacent both reduced thickness substantially at the leading and trailing. we

edges less than that of the adjacent portions of said base wall, said reduced thickness portion adjacent the leading edgebeing folded upon itself, forming a short radius bend defining the nose of the blade, the rearward portion of said base wall outwardly of said trailing edge recess also havingfa tapered marginal edge, and a complementary blade wall of sheet metal supported in mating relation on said base wall, said complementary wall being shaped to form the upper face of said blade and having a contoured edge interfitting and fairing with said tapered marginal edge 'of said forward wall portion, the opposite edge of said complementary blade wall interfitting and fairing with said trailing edge recess and said tapered edge to form the trailing edge of the blade, said walls being thereof.

3. A hollow sheet metal fluid-turning blade having leading and trailing edges'and a predetermined airfoil contour as assembled comprising a base wall of sheet metal shaped to form the lower face of said blade and having spanwise recesses inwardly of and adjacent both leading and trailing edges thereof forming portions of face of said blade and having contoured edges fitting within and fairing with both said tapered marginal edges of said base wall, said walls being bonded together at the contiguous interfittingportions thereof.

4. A hollow sheet metal fluid turning blade having a nose and a trailing edge and having a predetermined airfoil contour on both its upper and lower faces as as sembled comprising a base wall of sheet metal shaped to form one face of said blade and having a spanwise recess located inwardly of one edge thereof leaving a narrow outer portion separated by a portion of reduced thickness substantially at the leading edge less than that of the adjacent portions of said base wall, said portion of reduced thickness being folded upon itself forming a short radius bend'th'e outer surface of which defines said nose of the blade and having said narrow outer portion projecting upwardly and toward the trailing edge of the blade, and a complementary blade wall of sheet metal supported in mating relation on said base wall, said complementary wall being shaped to form the opposite face of said blade and having, a contoured edge fitting within and fairing with said narrow outer edge portion of said base wall, said walls being bonded together at the contiguous interfitting portions thereof.

'5. A hollow sheet metal fluid turning blade having leading and trailing edges, and having a predetermined airfoil contour as assembled comprising a base wall of sheet metal shaped to form one face of said blade and having a spanwise recess inwardly of and adjacent both leading and trailing edges thereof forming portions of reduced thickness less than that of the adjacent portions of said base wall and leaving a narrow portion of said base wall outwardly of said. leading edge recess, said leading edge recess being located substantially at the leading edge, said leading edge reduced thickness portion being folded upon itself forming a short radius bend the outer surface of which defines the nose of the blade and having a narrow marginal edge extending upwardly and toward the trailing edge of the blade, and a complementary-blade wall of sheet metal supported in mating relation onsaid base wall, said complementary wall being shaped to form the opposite face of said blade and hav ing a contoured edge fairing with said narrow marginal edge of said base wall, said walls having cooperating interfittingportions at their opposite edges forming the trailing edge of the blade, and said walls being bonded together at the contiguous interfitting portions thereof.

760,328 France Dec.6,1933 

